Like a magnificent volcano threatening to erupt, plumes of steam rise from the mountain in the farmyard. Every day, about a tonne of horse muck and bedding from the 20 or so stabled horses is added to the muck heap – a small car’s weight in manure.
The heap is shaped and piled by the digger into its mountainous form, to encourage effective rotting. It’s a hub for birdlife, rich in beetles, worms and insects. House sparrows flit over its surface, looking for tasty grains from horse feed, or soft arthropods such as larvae for their nestlings. Jackdaws forage on the craggy ravines, lending an air of drama. Pied wagtails hop about at base camp. Swallows skim its heights, feasting on the clouds of tiny cluster flies.
I still remember proudly the day my primary school visited the farm in the 1980s. In a moment when the teacher’s back was turned, I persuaded everyone how much fun it is to play in the muck heap. A feral bunch of us climbed to the top, ignoring the cries of despair from school staff, our hands sinking into the burning hot muck, and then jumped, free and glorious, from the summit into dark pools of effluent.
The temperature inside the heap can reach well over 50C as it decomposes. This level of heat kills eggs and larvae from parasites, showing the importance of this effective rotting over six months or so. Twice a year the heap is spread on the fields, replacing artificial fertiliser.
Recently I visited a nearby large-scale arable farm and discovered the Japanese practice of bokashi. This involves adding live microbes to cattle manure collected from local farms. The bacteria stimulate fermentation and increase nutrient availability, aiding crop growth. Bokashi also reduces emissions such as ammonia and carbon dioxide. It was noticeable standing next to the inoculated manure that there was no obvious smell. This innovative approach, unusual in the UK, brings significant benefits to both environment and productivity.
You might think the hay barn, gradually filling with this year’s sweet-scented bales of goodness, is the heart of the farm. Yet as I visit each day, pilgrim-like with my barrow of offerings for the great steaming god, I happen to think it is the muck heap.
• Country diary is on Twitter at @gdncountrydiary
• Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 (Guardian Faber) is published on 26 September; pre-order now at the guardianbookshop.com and get a 20% discount
